Permeable depolarizing mass and process obi making the same



Feb. 26 1,484,780

(3. W. HEISE ET AL PERMEABLE DEPOLARIZING MASS AND PROCESS OF MAKING THE SAME Filed NOV. 15. 1921 Patented Feb. 25, 1924!.

UNITED STATES PATENT OFFICE.

GEORGE 7. 111315515, OF ELMI-IUIQST, YORK, CLARENCE 'W. BROKATE, OF DA1\T- BURY, OHIO, ASSIGNORS TO UNION CARBIDE 5t CARBON RESEARCH LABORATORIES,

INC'., A. CORPORATION OF NEW YORK.

PERMEABLE DEPOLARIZING IJIASS AND PROCESS OF MAKING THE SAME.

Application filed November 15, 1921.

Z '0 all whom it may concern:

Be it known that we, GEORGE W. llsi'sn and CLARENCE WV. Bnoxa'rn, citizens of the United States, residing at Elmhurst and Danbury, respectively, in the counties of Queens and Ottawa and States of New Yorl: and Ohio, have invented certain new and useful Improvements in Pe .nieable Depolan izing Masses and Processes of Making the Same, of which the following is a specification.

This invention relates to dry cells and has particular reference to improvements in de polarizers for such cells. A principal object of the invention is to provide depolarizing bodies capable of rapidly absorbing water.

In making up depolarizing mix f r dry cells, according to prior practice, water or electrolyte solution has been used to bring the comminuted and intermingled manganese dioxide, carbon and electrolyte salts into plastic condition for tamping or mold ing. If the shaped masses of depolarizer so made are allowed to dry out, the salts crystallize from the gradually concentrating solution diffused throughout the depolarizer and cement the mix particles together to form a hard mass very slowly permeable by water. I have discovered that by using a non-aqueous liquid, or a liquid containing a relatively small amount of water, as the plasticizing agent, it is possible to make a readily permeable depolarizing body having adequate coherence and hardness.

Our invention will be described in connection with the tubular masses of dcpolarizer carrying a central carbon rod and referred to in the trade as mix bobbins. It is to be understood, however, that the invention is applicable to the preparation of any type of depolarizing mass in which a high rate of water absorption is desirable.

In the manufacture of mix bobbins it is the practice to tamp the depolarizing mix, moistened With water, about a carbon rod, or to mold a tubular body of moist mix and then force a carbon rod into the central perforation. Bobbins so formed maybe allowed to dry, after Which they may be wrapped in fabric, such as cheese cloth, and immersed in water for a considerable time so that they may take up an adequate amount of moisture before assembly with Serial No. 515,366.

the other cell elements. According to our invention the manufacture of cells of this kind is considerably expedited, asthe improved bobbins acquire in a few minutes a water content at least equal to that of bobbins of the old type after long immersion.

Furthermore, the difliculty with which water penetrates bobbins made according to prior practice is a marked disadvantage when they are to be used in dry cells of the water activated type. Deferred action cells containing moisture and adapted to be a'ctived by insertion of one of the electrodes are sub jcct to deterioration through drying out on standing. lVater activated cells, on the other hand, are free from this defect and from the corrosion which is frequently caused by the presence of liquid. The chief objection to their use has heretofore been the slowness with which water is taken up. A period of several hours is usually required and it is in general necessary to add the water in small quantities at intervals. By the preparation of the depolarizer as described herein, the time required for activation may be reduced to a few minutes.

As noted above, a non-aqueous liquid or one containing a relatively small proportion of water, is used in rendering the mix plastic. A number of liquids may be used, for example, ethyl alcohol, methyl alcohol, and benzene. The basic idea of our invention is the use of a plasticising liquid in which the electrolyte salts are insoluble, or of a liquid capable of dissolving the salts in whole or in part but yieldingon evaporation a deposit which does not bind the mix particles together into a diflicultly permeable mass. In general, any liquid, or mixture of liquids, having these characteristics and capable of giving temporary or permanent coherence to the mix is suitable for use in preparing a readily permeable depolarizer.

Any suitable depolarizing composition may be adopted and may be worked up into bobbins or other shapes in the usual manner, a liquid of the type above defined being used instead of water. The electrolyte salts will in general be zinc chlorid and ammonium chlorid. Ethyl alcohol of about 95% is preferred for agglomerating the mix. Both of the salts referred to are dissolved by alco- 1101, but they are generally present in amount substantially exceeding the solvent capacity or the quantity of alcohol used. l[ have found, moreover, that even though these salts be dissolved in part by the alcohol, the evaporation of the solvent does not result in the formation of diihcultly permeable mass. The solvent may be diluted with water to some extent without material loss of per inability in the molded i The alcohol may be denatured, provided the added substance would not exert a detrimental influence on the cell. Bobbins prepared as described will usually be dried be fore use and substantially all of th alcohol will evaporate before the cell is a nbled. However, if: a oortion of the alcohol remains will do no harz'n. The re novai of the liquid may be enpedi ed by oderate heat,

rub SUCilOH, or the hire, ii ocsieo, and means ecovery of vapors.

may be provided i The bobbins may be wrapped in fabric or be provided with other forms of surface pro tection, according to well known methods.

Que embodiment oi our invention will be described in connection with the accompanying drawing in which the figure is a vertical longitudf ial section through a dry cell of the water activated type.

Reference numo 2 denotes a zinc container aectrode h rlllg a dry molded mix bobbin therein, comprising carbon and manganese (llOXld. The bobbin spaced from the sides and bottom of the container, and the space between these two parts is filled by a dry paste-forming material 4:, of any suitable kind.

A. longitudinally perforated carbon electrode open at both ends, passes cent-rally through the mix. A plurality of transverse perfor tions 6 afford communication between the mix anl the interior of the carbon electrode. A seal "4' and a non-conducting disc 8 are fitted in the upper end of the zinc contai er 2, above the mix, and the carbon elect-rode Jasses tln'ough a central perforation in the seal, and disc. A. corlr 9 or othr closing means is provided for the. openii in the upper end of the carbon electrode. a some instances a vent l0 having a stopper ll is arranged in the seal to facilitate the escape of air.

To put the cell in action, water is added through th opening in the projecting end 01": the carbon electrode. The stopper 11 will be temporarily removed to facilitate the escape or" air which is displaced by the liquid. The mi}: is rapidly penetrated by the water emerging from the hollow carbon through perforations 6, and the dry pasteiforming material is moistened by contact with the saturated mix, as Well as by the escaoe oi"- waer from the bottom of the carbon electrode. The salts are dissolved as the water traverses the mix and the resulting electrolyte solution is uniformly dis-- tributed through the cell.

The paste may be of any suitable kind, but an exceedingly rapid activation may be obtained by the use of 1 dry granular pastelorming material of the type described in the application of ll. 0. Bonner and H. F. French Serial No. 356,496, filed February 5, 1920. Such a material may be, for eX- ample, coarse ground cereals, granulated uncooked fiour paste, agar-agar, etc. It is charact r stic of such substances to be readily permeable to liquids such as water or water containing electrolytx A. dry cell embody ing the combination of a readily permeable 311i): bobbin prepared according to this invention, and a dry granular paste-forming material offers very slight opposition to the The absorpoiilusion of activating liquid. tire capacity of the permeable mix is high, so that a relatively large amount of liquid may be stored in the cell. The increased permeability is not accompanied by any segregation of mix particles increasing the internal resistance of the cell.

l Vater may obviously be added in other ways than through a hollow carbon electrode, and the permeable mix may be bumped into the cell, instead of being molded. It is possible in some cases, also, to omit part or all of the electrolyte salts from the mix and to use an. electrolyte solution for inpregnating or activating. Various other departures from the particular embodiment described herein may be made within the scope of the appended claims.

Vie claim:

1. A process of preparing a depolarizer containing electrolyte salts which operate, upon separation from water solution, to render the depolarizer diilicultly permeable, comprising associating with the ingredients of the dopolarizer liquid which does not contain water in amount sufficient to dissolve said salts, shaping said depolarizer, and removing said liquid therefrom.

2. ill process of preparing a depolarizer comprising forming mixture of a finely divided reducible compound, a conductive material, and an electrolyte salt and making said mixture plastic by incorporating therewith a liquid. adapted to be ren'ioved without renderl 1g said mixture difficultly permeable, and removing said liquid therefrom.

3. The invention according to claim 2, in which the liquid is an organic compound.

l. The invention according to claim 3, in which the liquid is an alcohol.

5. The invention according to claim a, in which the alcoholic liquid contains ethyl alcohol.

6. The invention accordingto claim 5, which the alcoholic liquid is ethyl alcohol of approximately 7. A. coherent, substantially dry depolarizing composition comprising; conductive and depolarizing materials bonded with electrolyte salt in a condition permitting rapid liquid absorption by the composition.

8. A coherent depolarizing composition such as may be prepared by bonding conductive and depolarizing materials with electrolyte salt deposited in situ from an organic liquid.

9. A substantially dry formed body comprising man 'anese depolarizer, a conductive material, and electrolyte salts, said salts being present in a form devoid of the permeation-inhibiting properties of electrolyte salts deposited in situ from aqueous solution.

10. A coherent de-polarizer comprising a 3 finely divided reducible compound, a conductive material, and an electrolyte salt, a relatively small portion only of said salt being encrusted upon the said compound and material.

11. A coherent depolarizer readily permeable by Water, comprising a finely divided reducible compound, a conductive material, and an electrolyte salt, the major portion of said salt being without bonding action upon said depolarize-r.

12. The invention according to claim 11, in which the depolarizer is in the form of a mix bobbin 13. A mix bobbin for dry cells comprising eomminuted manganese dioxid and conductive carbon, together with Zinc chlo-rid and ammonium chlorid, no substantial part of said salts having a crystalline form produced by deposition from solution whereby ready permeability of the bobbin by Water is obtained.

14. A dry cell adapted to be activated by the addition of Water, and comprising a co herent depolarizer readily permeable by Water.

15. A dry cell comprising a zinc container electrode, a longitudinally perforated carbon electrode having transverse passages, a paste-forming material adjacent said c011- tainer electrode, and a readily permeable coherent depolarizing mix surrounding said carbon electrode and adjacent the pasteforming material.

16. The invention according to claim 15, in which a dry granular paste forming material is used.

In testimony whereof, We afiix our signatures.

GEORGE W. HEISE. CLARENCE W. BROKATE. 

